The proposed investigation comprises an attempt to discover the relationship between children's spontaneous social-context speech and crib speech and an attempt to determine the role of crib speech in children's acquisition of their first language. The data of concern were obtained by weeking sampling of the spontaneous speech of fourteen children. Both social-context speech samples will be compared with the crib speech samples on a number of dimensions (including linguistic practices) in order to determine the relations between children's speech in the two sampling contexts. These analyses of a longitudinal sample should clarify the role of crib speech and linguistic practice in children's acquisition of their native tongue.